Fan motor with anti-dirt sticking function and apparatus having fan motor

ABSTRACT

A fan motor including a stator; a rotor having a cylindrical part arranged around the stator and a plurality of blades sticking out from an outer periphery of the cylindrical part to a radial direction, the rotor rotating about an axial line to blow a gas; and a housing having a disk part arranged at a side of the stator, a shroud part arranged around the blades, and a plurality of stays extending from an outer circumferential edge portion of the disk part to the radial direction to connect the disk part and the shroud part beside the blades. The stays are arranged at an upstream side from the blades in a blowing direction of the gas.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a fan motor with an anti-dirt sticking function and to an apparatus having a fan motor, which is used for a machine tool or robot, etc.

2. Description of the Related Art

In general, a machine tool or robot is used in an environment pervaded by dust, refuse, cutting fluid mist, etc. For this reason, when providing a fan motor (also referred to as a “cooling fan”) for cooling the electronic devices, etc. used for a machine tool or robot, operation of the fan motor causes the dust and other air-borne matter to collect at the fan motor and stick to the fan motor. If air-borne matter sticks to the fan motor in this way, operation of the fan motor will be obstructed and the cooling performance will deteriorate. As an apparatus for preventing such deterioration of the cooling performance, in the past, the apparatus described in Japanese Patent Publication No. 4775778 (J4775778B) has been known. The apparatus described in JP4775778B provides a nozzle near the fan motor and ejects compressed air from the nozzle to thereby remove air-borne matter stuck to the fan motor.

However, in a configuration like the apparatus which is described in JP4775778B which ejects compressed air from a nozzle to the fan motor, air-borne matter is forcibly blown into the fan motor, for example, into the clearance between the stator and rotor of the motor, and sticks inside the motor. Due to this, operation of the fan motor is conversely liable to be obstructed.

SUMMARY OF THE INVENTION

A fan motor of one aspect of the present invention includes: a stator having a coil; a rotor having a cylindrical part arranged around the stator and a plurality of blades sticking out from an outer periphery of the cylindrical part to a radial direction, the plurality of blades being arranged in a circumferential direction, the rotor rotating about an axial line to blow a gas in parallel to the axial line through the blades; and a housing having a disk part arranged at a side of the stator, a shroud part arranged around the blades, and a plurality of stays extending from the outer circumferential edge portion of the disk part to the radial direction to connect the disk part and the shroud part beside the blades, the plurality of stays being arranged in the circumferential direction, wherein the stays are arranged at an upstream side from the blades in a blowing direction of the gas.

Further, an apparatus having a fan motor of another aspect of the present invention includes: the above fan motor; a passage-forming member forming a passage through which cooling air generated by driving of the fan motor passes; and a cooled member cooled by the cooling air passing through the passage.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects, features, and advantages of the present invention will become clearer from the following description of embodiments in relation to the attached drawings. In the attached drawings,

FIG. 1A is a front view which shows the general configuration of an apparatus which has fan motors according to an embodiment of the present invention,

FIG. 1B is a perspective view which shows the general configuration of an apparatus which has fan motors according to an embodiment of the present invention,

FIG. 2 is a perspective view which shows the overall configuration of the fan motors of FIG. 1A and FIG. 1B,

FIG. 3 is a cross-sectional view cut along the line III-III of FIG. 2,

FIG. 4 is a view along the arrow IV of FIG. 3,

FIG. 5 is a perspective view which shows the configuration of a fan motor of a comparative example of an embodiment of the present invention,

FIG. 6 is a cross-sectional view cut along the line VI-VI of FIG. 5,

FIG. 7 is a view which shows a modification of FIG. 3,

FIG. 8 is a view which shows another modification of FIG. 3,

FIG. 9 is a view which shows a modification of a fan motor according to an embodiment of the present invention,

FIG. 10A is a view which shows a modification of FIG. 1A,

FIG. 10B is a view which shows a modification of FIG. 1B,

FIG. 11A is a view which shows another modification of FIG. 1A, and

FIG. 11B is a view which shows another modification of FIG. 1B.

DETAILED DESCRIPTION

Below, referring to FIG. 1A to FIG. 6, a fan motor according to an embodiment of the present invention will be explained. FIG. 1A and FIG. 1B are a front view and a perspective view which show the general configuration of an apparatus 100 having a fan motors according to an embodiment of the present invention. This apparatus 100 is an apparatus for cooling various devices which are provided at a robot or machine tool, etc. which is used in an environment pervaded by dust, refuse, cutting fluid mist, etc. (these being sometimes referred to all together as “air-borne matter”).

As shown in FIGS. 1A and 1B, the apparatus 100 has a radiator 101 and a case 102 which are placed next to each other, a first fan motor 110 and second fan motor 120 which are respectively provided at the radiator 101 and the case 102, and electronic devices 103 which are cooled by the fan motors 110 and 120. The electronic devices 103 include a control circuit for controlling a drive motor of the robot or machine tool (for example, a servo motor). The radiator 101 and the case 102 are formed overall as substantially box shapes. The case 102 are fastened to the radiator 101.

The radiator 101 is configured by a plurality of substantially rectangular shaped thin sheet fins 104 a which extend from a side surface 101 a to a side surface 101 b at the opposite side, extend in the up-down direction, and are separated from each other (see FIG. 10B). Air passages AP are formed in the up-down direction between adjoining fins 104 a. A top surface and bottom surface of the radiator 101 are open. At the bottom surface, an inlet 105 is formed, while at the top surface, an outlet 106 is formed. At the top surface of the radiator 101, the first fan motor 110 is arranged facing the outlet 106. Due to rotation of the fan motor 110, as shown by the arrow mark in FIG. 1A, cooling air flows through the radiator 101 and fan motor 110 from the bottom to the top.

The case 102 has an outlet 107 at its top surface. The second fan motor 120 is arranged below the outlet 107 while facing the outlet 107. Below the fan motor 120, a plurality of electronic devices 103 are arranged. If the fan motor 120 rotates, air is sucked in from a not shown inlet to the inside of the case 102 and is discharged from the outlet 107. Due to this, air flows along the surface of the electronic device 103 whereby the electronic devices 103 are cooled.

The electronic devices 103 are supported while contacting the radiator 101. For this reason, when rotation of the first fan motor 110 causes cooling air to flow through the passages AP in the radiator 101, the heat which is generated by the electronic devices 103 is dissipated through the radiator 101. In this way, in the present embodiment, since a pair of fan motors 110, 120 are provided at the apparatus 100, the air which flows through the radiator 101 and the air which flows through the inside of the case 102 enable the electronic devices 103 inside of the case 102 to be efficiently cooled.

Next, the configuration of the fan motors 110, 120 according to an embodiment of the present invention will be explained. FIG. 2 is a perspective view which shows the overall configuration of the fan motors 110, 120 (view seen from above at a slant), while FIG. 3 is a cross-sectional view cut along the line III-III of FIG. 2. In FIG. 3, only one side from the center axis of the fan motors 110, 120 (axial line L0 which extends in top-bottom direction) is shown. As shown in FIG. 2 and FIG. 3, each of the fan motors 110, 120 has a stator 10 which is configured and arranged about the axial line L0, a rotor 20 which rotates about the axial line L0, and a housing 30 which is arranged around the rotor 20.

The stator 10 has a substantially cylindrically shaped iron core 11 which has a plurality of projecting parts which project out in the radial direction, and a coil 12 which is wound around these projecting parts and form a plurality of stator poles. The rotor 20 has a shaft 21 which is arranged at the inside of the iron core 11 and extends along the axial line L0, a cylindrical part 22 which is arranged about the axial line L0 and around the stator 10, a plurality of blades 23 which stick out in the radial direction from the outer periphery of the cylindrical part 22 and are arranged at regular intervals in the circumferential direction, and a disk part 24 which connects the top end part of the shaft 21 and the top end part of the cylindrical part 22 above the stator 10. At the inner circumference of the cylindrical part 22, a plurality of permanent magnets 25 which form a plurality of rotor magnetic poles and are arranged in the circumferential direction, are attached.

FIG. 4 is a view along an arrow IV of FIG. 3 (view seen from below). In FIG. 4, illustration of the stator 10 and the rotor 20 is omitted. As shown in FIG. 3 and FIG. 4, the housing 30 has a disk part 31 which is arranged below the stator 10, a cylindrically shaped shroud part 32 which is arranged about the axial line L0 and around the blades 23, and a plurality of stays 33 (in the figure, four) which extend from the outer circumferential edge portion of the disk part 31 in the radial direction and connect the disk part 31 and shroud part 32 below the blades 23 and are arranged in the circumferential direction. The outer periphery 31 b of the disk part 31 is substantially positioned on the downward extension of the outer periphery of the cylindrical part 22.

As shown in FIG. 3, the stays 33 have top surfaces 331 which face the blades 23 and bottom surfaces 332 at the opposite sides. At the top surface 311 of the disk part 31, a recessed part 31 a is formed. In the recessed part 31 a, a printed circuit board 34 which is supported by the disk part 31 is held. That is, the recessed part 31 a functions as a holding part of the printed circuit board 34. The printed circuit board 34 is an electronic device (board) which controls the current which is supplied to the coil 12. At the inner circumferential edge of the disk part 31, a cylindrical part 35 is provided facing upward in a protruding manner. At the inside circumference of the cylindrical part 35, a pair of top and bottom bearings 36 are supported. At the insides of the bearings 36, a shaft 21 is rotatably supported.

Next, the operation of an apparatus 100 having the fan motor according to the present embodiment will be explained. Below, the case of using an apparatus 100 in an environment pervaded by cutting fluid mist will be explained. If drive current is supplied to the coil 12 of the stator 10 through the printed circuit board 34, the fan motors 110, 120 rotate. Due to this, air is sucked in from below the fan motors 110, 120 and is blown out upward, as shown by the arrow of FIG. 2. At this time, along with the flow of air, cutting fluid mist also flows toward the fan motors 110, 120.

In the present embodiment, the stays 33 are arranged below the blades 23, i.e., at the upstream side in the flow of cooling air. For this reason, the cutting fluid mist which flows toward the fan motors 110, 120 strikes the stays 33, and thus can be prevented from entering between the rotor 20 (cylindrical part 22) and stator 10. This point will be explained while using FIG. 5 which shows the configuration of a fan motor 130 of a comparative example of the present embodiment and FIG. 6 which is a cross-sectional view cut along the line VI-VI of FIG. 5. FIGS. 5 and 6 and FIGS. 2 and 3 differ in the arrangement of the stays 33. In FIGS. 5 and 6, the same constituents as FIGS. 2 and 3 are assigned the same referential marks.

In FIGS. 5 and 6, the stays 33 are arranged above the blades 23, i.e., at the downstream side of the cooling air. In this configuration, the cutting fluid mist which flows into the fan motor 130 strikes the bottom surfaces of the stays 33 whereby, as shown by the arrow A of FIG. 6, the cutting fluid mist is liable to enter between the rotor 20 and stator 10. If the cutting fluid mist enters the inside of the motor and the cutting fluid mist sticks to the inside of the motor, the rotation of the fan motor 130 will be obstructed. As a result, the fan motor 130 will fall in durability and it will become difficult to stably cool the electronic devices 103 over a long period of time. Further, in the configuration of FIGS. 5 and 6, the cutting fluid mist which collects at the top surfaces of the stays 33, as shown by the arrow B of FIG. 6, enters the clearance between the cylindrical part 35 and the shaft 21, whereby the bearings 36 are liable to decline in lifetime.

On this point, in the present embodiment, as shown in FIG. 3, the stays 33 are arranged at the upstream side in the cooling air, so the cutting fluid mist which strikes the stays 33 can be prevented from entering inside the motor and the fan motors 110, 120 can be rotated well in an environment pervaded by the cutting fluid mist. As a result, the fan motor 130 rises in durability and stable cooling performance of the apparatus 100 can be obtained. Further, the stays 33 are arranged at the bottom of the fan motors 110, 120, so cutting fluid mist can be prevented from entering the clearance between the cylindrical part 35 and the shaft 21 and a drop in lifetime of the bearing 36 can be prevented.

FIG. 7 is a view which shows a modification of FIG. 3. In FIG. 7, the stator 10 and the printed circuit board 34 are surrounded by a nonconductive resin material 15. Due to this, cutting fluid mist, etc. can be prevented from sticking at the stator 10 or the printed circuit board 34. If covering the surroundings of the stator 10 and the printed circuit board 34 by the resin material 15, the clearance 16 a between the permanent magnets 25 and the stator 10 becomes smaller. For this reason, if cutting fluid mist enters the clearance 16 a, the cutting fluid mist will easily stick there. Therefore, it is necessary to reliably prevent entry of cutting fluid mist to the clearance 16 a. On this point, as illustrated, it is effective to arrange the stays 33 at the upstream side of the cooling air.

FIG. 8 is a view which shows another modification of FIG. 3. In FIG. 8, the top surface 311 of the disk part 31 and the top surfaces 331 of the stays 33 are slanted downward toward the outside in the radial direction, i.e., to the opposite side in the blowing direction of the cooling air, whereby slanted parts 311 a, 331 a are formed. In FIG. 8, although a resin material 15 is provided around the stator 10, the resin material 15 may also be omitted. By providing the slanted parts 311 a, 331 a at the top surfaces 311, 331 of the disk part 31 and stays 33 in this way, when cutting fluid mist enters the clearance 16 b between the rotor 20 (cylindrical part 22 and permanent magnets 25) and the disk part 31, the cutting fluid mist is ejected along the slanted parts 311 a, 331 a to the outside in the radial direction and the cutting fluid mist can be prevented from sticking at the clearance 16 b.

The stays 33 which are arranged at the upstream side from the blades 23 in the blowing direction of the cooling air may be configured in various ways other than that explained above. FIG. 9 is a perspective view of fan motors 110 and 120 which show one example (view seen from slant below). In FIG. 9, illustration of the housing 30 is partially omitted. As shown in FIG. 9, the bottom surface 332 of the stay 33 is slanted in the up-down direction (short direction) across the entire length in the diametrical direction. The cross-sectional shapes of the stays 33 in the short direction are triangular shapes. Due to this, the flow of air at the bottom surfaces 332 of the stays 33 becomes smooth and the flow rate characteristics of the fan motors 110 and 120 can be improved.

In the above embodiment (FIG. 1A and FIG. 1B), although the first fan motor 110 is arranged at the top part of the radiator 101, the configuration of the apparatus 100 is not limited to this. FIGS. 10A and 10B are views which show a modification of FIGS. 1A and 1B. In FIGS. 10A and 10B, the first fan motor 110 is arranged facing the inlet 105 at the bottom of the radiator 101. According to this configuration, the air which is sucked in by the first fan motor 110 passes through the radiator 101 and is discharged from the outlet 106. In each of the configurations of FIGS. 1A and 1B and FIGS. 10A and 10B as well, the axial line L0 is directed toward the vertical direction and the stays 33 are arranged below relative to the blades 23, so the cutting fluid mist can be prevented from entering the bearings 36 due to gravity.

FIGS. 11A and 11B are views which show another modification of FIGS. 1A and 1B. In FIGS. 11A and 11B, at the side surface of the radiator 101, an inlet 105 is provided, while at the top and bottom surfaces, outlets 106 are provided. The first fan motor 110 is arranged facing the inlet 105 at the side portion of the radiator 101. That is, the axial line L0 of the fan motor 110 extends in the horizontal direction. According to this configuration, the air which is sucked in by the first fan motor 110 flows through the inside of the radiator 101 upward and downward, and is discharged from the top and bottom outlets 106. As shown in FIGS. 11A and 11B, when providing the fan motor 110 at the side surface of the radiator 101, it is possible to keep dirt from being sucked in from the floor surface or dirt from dropping down from above to the fan motor 110. The fan motor 110 may also be arranged with an axial line L0 other than in the vertical direction and horizontal direction, i.e., in the slanted direction.

The above embodiment and modifications can be further modified in various ways. For example, in FIG. 7, although the circumferences of the stator 10 and the printed circuit board 34 are covered by a resin material 15, just one of either of these may also be covered by the resin material 15. In FIG. 8, although both the disk part 31 and the stays 33 of the housing 30 are provided with slanted parts 311 a, 331 a which slant to the opposite side in the blowing direction of the cooling air, just one of either of these may also be provided with slanted parts. In FIG. 9, although the surfaces 332 of the stays 33 at the upstream side in the blowing direction of the cooling air are provided at a slant with respect to the axial line L0 and the stays 33 are made triangular shapes in cross-section, they may also be made trapezoidal shapes in cross-section. Although the disk part 31 of the housing 30 is provided with a holding part 31 a for holding the printed circuit board 34 (FIG. 3), this may also be omitted.

In the above embodiment, the first fan motor 110 and the second fan motor 120 are configured the same. However, they may also be configured different from each other. Either of the first fan motor 110 and the second fan motor 120 (for example, the second fan motor 120) may be omitted to configure the apparatus 100. In the above embodiment, although passages AP through which cooling air generated due to driving of the first fan motor 110 passes are formed by the radiator 101, the configuration of the passage-forming member is not limited to this. In the above embodiment, although the electronic device which controls the drive motor of the robot or machine tool is included in the electronic devices 103 cooled by the cooling air which flows through the radiator 101, the cooled member may be any member.

In the above embodiment, although the fan motors 110, 120 are used for the apparatus 100 which cools electronic devices 103 which are provided at a robot or machine tool, a fan motor and an apparatus having a fan motor of the present invention may also be similarly applied to other machinery. It is also possible to blow something other than cooling air to the fan motor. The gas which is below in parallel to the axial line L0 through the blades 23 is not limited to cooling air.

The above embodiment can be freely combined with one or more of the modifications.

According to the present invention, the stays of the fan motor are arranged at the upstream side from the blades of the fan motor in the blowing direction, so air-borne matter which strikes the stays can be prevented from entering the inside of the motor and sticking of air-borne matter at the inside of the motor can be prevented.

While the present invention has been described with reference to the preferred embodiments thereof, those skilled in the art would understand that various modifications and changes may be made thereto without departing from the scope of the appended claims. 

1. A fan motor comprising: a stator having a coil; a rotor having a cylindrical part arranged around the stator and a plurality of blades sticking out from an outer periphery of the cylindrical part to a radial direction, the plurality of blades being arranged in a circumferential direction, the rotor rotating about an axial line to blow a gas in parallel to the axial line through the blades; and a housing having a disk part arranged at a side of the stator, a shroud part arranged around the blades, and a plurality of stays extending from an outer circumferential edge portion of the disk part to the radial direction to connect the disk part and the shroud part beside the blades, the plurality of stays being arranged in the circumferential direction, wherein the stays are arranged at an upstream side from the blades in a blowing direction of the gas.
 2. The fan motor according to claim 1, further comprising a printed circuit board on which an electronic device controlling a current supplied to the coil is mounted, wherein the disk part has a holding part holding the printed circuit board.
 3. The fan motor according to claim 2, wherein at least one of the stator and the printed circuit board is surrounded by a resin material.
 4. The fan motor according to claim 1, wherein at least one of the disk part and the stays have a slanted part slanted to an opposite side of the blowing direction of the gas toward an outside in the radial direction.
 5. The fan motor according to claim 1, wherein surfaces at upstream sides of the stays are slanted with respect to the axial line.
 6. An apparatus having a fan motor, comprising: a fan motor according to claim 1; a passage-forming member forming a passage through which cooling air generated by driving of the fan motor passes; and a cooled member cooled by the cooling air passing through the passage.
 7. The apparatus having a fan motor according to claim 6, wherein the cooled member is an electronic device for controlling a drive motor of a robot or machine tool.
 8. The apparatus having a fan motor according to claim 6, wherein the fan motor is arranged with the axial line facing a vertical direction and with the stays facing downward. 